The invention concerns a device and a method for choking a stock suspension flow in a paper machine or system for stock treatment.
For choking fluid flows, valves of various designs are prior art. A considerable disadvantage of these standard valves, such as ball valves, needle valves, flap valves, slide valves and similar, is that for generating the desired flow resistance they must create very narrow cross sections, which normally tend to clogging when the fluid passing through them carries fibers.
Reference is made to the unpublished German patent application P 42 39 643. It presents a throttle device which for choking a fluid flow essentially utilizes turbulence phenomena which occur or are generated therefor and, thus, can dispense with narrow cross sections. An unfavorable characteristic of this device is its limited working range.
The problem underlying the invention is to describe a throttle device which is suited specifically for use in paper machines and, for one, is with regard to the clogging tendency less susceptible than the standard valves and, for another, has a working range greater than the throttle device presented in the aforementioned patent application. An example of a paper making machine in which the throttle device of the present invention can be used is disclosed in U.S. Pat. No. 4,050,479, which patent is expressly incorporated herein by reference.